Thursday, May 22, 2008
The Institute for Safe Medicine Practices, a non-profit group organized to improve drug safety and review the FDA's adverse-event reports, recently released a study on Chantix. The report indicated a greater spectrum of side effects, including heart trouble, seizures, and diabetes in addition to the effects already identified such as suicide and depression. Here's an excerpt from the Wall Street Journal:
Thomas Moore, the study's lead author and the institute's senior scientist for drug safety, called on Pfizer and the FDA to "immediately" strengthen Chantix's label warnings and rigorously examine emerging safety issues. "Based on the data available now, the existing warnings are completely inadequate," he said. "You'd expect a stop-smoking drug to have a relatively low number of reports," because it isn't used in high-risk patients.
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Mr. Moore's study links the drug to a greater spectrum of maladies. The report identified 173 injuries, including falls and traffic accidents, involving people taking Chantix that were possibly the result of such factors as muscle spasms, dizziness and confusion. The FDA data also contain 224 reports of potential heart-rhythm disturbances, 372 reports of possible movement disorders and 544 reports of likely glycemic problems, including diabetes.
After just months on the market, Chantix broke into the small group of medicines with more than 100 reports of serious injury. In the 2007 fourth quarter, with nearly 1,000 reports, it topped the group's list of 769 drugs examined in the U.S. for serious side effects. By contrast, the median number of serious-injury reports for other drugs is five. Most medications that came close to Chantix carry the FDA's most-serious "black box" warning, the study says.
The institute's findings have limitations. Using adverse-event reports doesn't establish a causal relationship between a drug and a side effect. Such reports are turned in by doctors, patients and sometimes plaintiffs' lawyers positing a connection but not proving one. Mr. Moore, who has consulted for plaintiffs' attorneys on drug issues, said the study isn't being published in a medical journal because he wanted to publicize the findings more promptly. A spokeswoman for the ISMP says that the group doesn't receive funding from plaintiffs' attorneys or other parties with a commercial interest in this report, and is primarily financed through subscriptions to its newsletter and grants.